A pinch valve is a full bore or fully ported type of control valve which uses a pinching effect to obstruct fluid flow.

Operating principle

Pinch valves employ an elastic tubing (sleeve/hose) and a device that directly contacts the tubing (body). Forcing the tubing together creates a seal that is equivalent to the tubing's permeability. Air-operated pinch valves consist of an elasticised reinforced rubber hose, a type of housing, and two socket end covers (or flanges). In air-operated pinch valves, the rubber hoses are usually press-fitted and centered into the housing ends by the socket covers. There is no additional actuator, the valve closes as soon as there is a pressurized air supply into the body. When the air supply becomes interrupted and the volume of air exhausts, the elastic rubber hose starts to open due to the force of the process flow.

Applications

Pinch valves are typically used in applications where the flowing media needs to be completely isolated from any internal valve parts. The sleeve will contain the flow media and isolate it from the environment, hence reducing contamination. They are commonly applied to medical instruments, clinical or chemical analyzers, and a wide range of laboratory equipment. They are used in some

water pistol A water gun (or water pistol, water blaster, or squirt gun) is a type of toy gun designed to shoot jets of water. Similar to water balloons, the primary purpose of the toy is to soak another person in a recreational game such as a water fight. ...

s, notably the original

Super Soaker Super Soaker is an American brand of recreational water gun that uses manually-pressurized air to shoot water with greater power, range, and accuracy than conventional squirt pistols. The Super Soaker was invented in 1989 by engineer Lonnie John ...

50.

Material selection

The sleeve material is selected among suitable

synthetic polymer Some familiar household synthetic polymers include: Nylons in textiles and fabrics, Teflon in non-stick pans, Bakelite for electrical switches, polyvinyl chloride (PVC) in pipes, etc. The common PET bottles are made of a synthetic polymer, polyet ...

based upon the corrosiveness and abrasiveness of the flow media. A key selection criterion is the operation temperature, which needs to be within the limit of the polymer. Several

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Types of polyisoprene ...

qualities are available for pinch valves such as

natural rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Types of polyisoprene ...

EPDM EPDM rubber (ethylene propylene diene monomer rubber) is a type of synthetic rubber that is used in many applications. EPDM is an M-Class rubber under ASTM standard D-1418; the ''M'' class comprises elastomers with a saturated and unsaturated co ...

nitrile In organic chemistry, a nitrile is any organic compound that has a functional group. The name of the compound is composed of a base, which includes the carbon of the , suffixed with "nitrile", so for example is called " propionitrile" (or pr ...

, viton,

neoprene Neoprene (also polychloroprene) is a family of synthetic rubbers that are produced by polymerization of chloroprene.Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf Krüger "Rubber, 4. Emulsion Rub ...

and

butyl In organic chemistry, butyl is a four-carbon alkyl radical or substituent group with general chemical formula , derived from either of the two isomers (''n''-butane and isobutane) of butane. The isomer ''n''-butane can connect in two ways, giv ...

. Different housings and end covers/flange materials such as

aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

plastics Plastics are a wide range of synthetic or semisynthetic materials composed primarily of polymers. Their defining characteristic, plasticity, allows them to be molded, extruded, or pressed into a diverse range of solid forms. This adaptab ...

and

stainless steel Stainless steel, also known as inox, corrosion-resistant steel (CRES), or rustless steel, is an iron-based alloy that contains chromium, making it resistant to rust and corrosion. Stainless steel's resistance to corrosion comes from its chromi ...

are also available.

References

{{DEFAULTSORT:Pinch Valve Valves